Dialectism

It was the scribe of y who replaced certain dialectisms and less usual forms by the common types, e.g. ...

Starting with Jungmann, the opinion that before the National Revival the Czech language was in decay (invaded by dialectisms, inappropriate neologisms, overwhelming loans from German, and so on) then spread ...

... the formal normative variety of the language as it is used today in formal writing by educated native speakers. As a result, we have eschewed dialectisms and regionalisms. The English variety employed in the book is formal British English, ...